Wireless communication systems employ various multiple access schemes in order to support the call load of multiple users. In such multiple access schemes, a number of radio resources or radio channels are available for communication between the Radio Access Network (RAN) and users. When a call is requested, radio resources are allocated from a pool of available resources for the duration of the call. When the call ends, the radio resources are re-inserted into the pool of available resources so that they may be allocated to other calls.
A Dynamic Channel Allocation (DCA) function is generally responsible for allocating radio resources when a call is requested. Sophisticated DCA methods determine an optimal allocation of resources amongst a set of available resources, such that certain system metrics are optimized. By way of example, typical system metrics include power consumption and interference.
When allocating system resources, the set of available resources for a particular request does not necessarily consist of all available system resources. For example, in Time Division Duplex (TDD) systems, a certain number of timeslots per frame are allocated for downlink (DL) transmission whereas the remainder are allocated for uplink (UL) transmission. In this case, DCA must restrict its choice for radio resources to DL timeslots for DL requests and to UL timeslots for UL requests. Similarly, a network operator might want to allocate radio resources for particular services. For example, in TDD systems, certain timeslots could be allocated for real time (RT) services whereas other timeslots could be allocated for non-real time (NRT) services.
In other types of wireless systems, the radio resources that are allocated for specific services could be frequency bands, channelization codes, timeslots, power units, and the like.
Ordinarily, radio resources cannot be straightforwardly divided between service types and direction because they have different requirements. Additionally, a number of characteristics are typically service-type and/or direction dependent. For instance, an offered load is the number of calls requested and the data rate of the requests. A call blocking rate is the rate at which call requests are blocked because radio resources are unavailable. A call dropping rate is the rate at which active calls prematurely end, such as due to a bad connection. User satisfaction is the percentage of users for which Quality of Service (QoS) requirements are met. QoS requirements include BLER (Block Error Rate), transmission delay and the like.
Data calls typically have a higher DL data rate than UL data rate. This is a result of the fact that user downloads typically far exceed uploads, causing a higher DL traffic load and asymmetric traffic. Similarly, RT calls typically have different QoS, call blocking and call dropping requirements than do NRT calls. Moreover, the radio resources to be allocated do not necessarily offer the same capacity to each service-direction combination. For example, in TDD systems, one timeslot might support more UL RT calls than DL RT calls, or vice versa. As a result, an operator cannot simply allocate twice as many timeslots for DL transmission if the DL offered load is twice the UL offered load.
Given these service-type and/or direction dependent requirements, determining the optimal allocation of available radio resources becomes a complex problem.
It would therefore be beneficial to determine an optimal allocation of radio resources without the limitations of the prior art.